This invention relates to an internal combustion engine test instrument and more particularly to a portable self-contained ignition system diagnostic instrument for testing single cylinder and multi-cylinder spark ignited engines.
In a gasoline engine ignition system, certain visible operating characteristics of the spark arc across the electrodes of the spark plug are indicative of the well being of the ignition system. Particularly, abnormal color, low intensity, or nonuniform firing frequency of the spark arc are indicative of unacceptable system performance.
Therefore, in diagnosing and troubleshooting an ignition system, it is desirable to test the ignition system from the position of the spark plug by observing the visual characteristics of the spark arc. Moreover, it is desirable to perform the testing under simulated operating conditions wherein the ignition system is functioning under a selectively variable "load", i.e., the spark arc being subject to varying amounts of compressed air.
It is also desirable that such a test/diagnostic instrument be portable, self-contained, and easy to use without the need for specialized equipment. Additionally, it is desirable that such a test instrument be economical and cost efficient to manufacture.
In accordance with the present invention, a portable, self-contained ignition system diagnostic/test instrument is disclosed which includes a housing having an interior spark chamber, a transparent portion permitting visual observation of the spark chamber, an outer portion for forming an exterior air pump chamber, and an air passageway connecting the outer portion and the chamber. A reciprocal transparent air pump sleeve assembly is moveably mounted about the outer portion of the housing in sealing engagement therewith with the pump sleeve assembly and outer portion of the housing forming an air pump chamber therebetween and coacting to pump air through the air passageway to pressurize the spark chamber upon reciprocation of the pump sleeve assembly. A check valve is operationally connected to the air passageway for maintaining air pressure with the spark chamber. A spark plug having a pair of electrodes forming a spark gap of predetermined size is mounted to the housing chamber in sealing engagement therewith so that the spark gap is positioned within the spark chamber and visible through the transparent portion. A ground wire for detachably grounding the spark plug to an engine ground is connected to the spark plug. A pressure gauge is operationally connected to the spark chamber for indicating pressure within the spark chamber.
Accordingly, it is an object of the present invention to provide a new and improved portable ignition system test/diagnostic instrument for testing both single cylinder and multi-cylinder gasoline engines.
Another object of the invention is to provide a test instrument that includes a self-contained means for varying "load", pressure, for testing an ignition system under variable "load" conditions, simulating compression in actual operation.
A still further object of the invention is to provide an ignition system test instrument that is easily operable without specialized equipment.
A further object of the invention is to provide a portable ignition system test instrument that is economical and cost efficient to manufacture.
Other objects will be in part obvious and in part pointed out more in detail hereinafter.